Nicotine is one of the major components of cigafette smoking which causes various systemic and local diseases to human body. Mitrogenic effects of nicotine to systemic disease are interesting factors in the results of cellular proliferation especially to vascular and pulminary tissus or cells. The study of local effects concerns with destruction of tissue and delayed healing rate after various surgicla treatment. Platelet-Derived Growth factor(PDGF) and Insulin-like growth factor(IGF) are known as major mitogens to human PDL cells. The purpose of this studywas to investgate the mitogenic effects of nicotine to human PDL cells. We studied the expression of PDGF-α receptor, PDGF-βreceptor, and IGF-1 receptor mRNA form the nicotine treated human PDL cells by northern analysis. The experimental groups were divided into different serum(1%, 10%) and nicotine(100ng/ml, 1000ng/ml) condentrations and each group was studied by time course. The results of this study showed upregulation of PDGF-α, β receptor and IGF-1 receptor mRNA at 100ng/ml nicotine concentration and 10% serum group to the time course. These results suggest that physiologically attainable nicotine concentrations may stimulate mitogenic gene synthesis to human PDL cells in vitro.